Filling packaging containers

ABSTRACT

A machine for filling packaging containers with a flowable product comprises a control valve in the form of a plug valve having a body defining a bore forming a frusto-conical valve seat, a plug having a complimentary frusto-conical surface, and a valve chamber for pressurized fluid formed at the wider end of the plug. The chamber communicates with the bore. The plug is axially displaceable between a first position, in which the frusto-conical surface seals against the valve seat and in which it is rotatable to control flow through the valve, and a second position, in which it is withdrawn into the chamber to provide clearance between the mating surfaces of the plug and the seat but retaining clearance between its wider end and the opposite surface of the chamber so that all surfaces of the plug are exposed for cleaning and sterilization.

BACKGROUND OF THE INVENTION

This invention relates to a machine for filling packaging containerswith a flowable product. The product is preferably a mixture of at leasttwo flowable components. Only two components will be mentionedhereinafter for the sake of clarity. The product may consist of a firstcomponent in the form of a particulate solid material suspended in aviscous liquid (hereinafter: solids), and a second component in the formof a thin liquid, e.g. water (hereinafter: liquid), each component beingsupplied from a separate source. Naturally both the components could beliquids but the terms "solids" and "liquid" will be used for simplicityof description. Examples, among foodstuffs, of products suitable forpackaging according to the invention include heterogeneous petfoodproducts and soups containing solid matter such as pieces of vegetables.

The invention is very suitable for aseptic filling processes, usingcontainers of synthetic plastics, rigid, semi-rigid or flexible.

The aim of the invention is to avoid or at least to mitigate thedisadvantages of known filling machines, some of which will be mentionedhereinafter.

SUMMARY OF THE INVENTION

The invention provides a machine for filling packaging containers with aflowable product, the machine comprising a control valve in the form ofa plug valve having a body defining a bore forming a frusto-conicalvalve seat, a plug having a complementary frusto-conical surface, avalve chamber for pressurized fluid being formed at the wider end of theplug, the chamber communicating with the bore, the plug being axiallydisplaceable between a first position, in which its frusto-conicalsurface seals against the valve seat and in which it is rotatable tocontrol flow through the valve, and a second position, in which it iswithdrawn into the chamber to provide clearance between the matingsurfaces of the plug and the seat but retaining clearance between itswider end and the opposite surface of the chamber so that all thesurfaces of the plug are exposed for cleaning and sterilization.

An important advantage of a filling machine having a valve designed asstated above is that when the plug is in the withdrawn position thewhole valve can be thoroughly cleaned and sterilized without having tobe dismantled. A further advantage is the ability of the above plugvalve to compensate for any differential expansion of the plug and itsvalve seat by the axial adjustability of the plug built into the designof the valve. This is of particular advantage when the seat definingbody and the plug are made of materials having different coefficients ofthermal expansion.

A further advantage of the plug valve is that the plug and its seat areable to survive abrasive attack by relatively hard particles in theproducts being filled by the machine, e.g. bone or gristle. Suchparticles have a damaging effect on prior art valves sealed byelastomeric O-rings which are vulnerable to the action of suchparticles, particularly when an "O" ring is slid past a port duringdismantling and assembly.

In a preferred embodiment the machine comprises conduit meanscommunicating with the valve chamber for leading the pressurized fluidinto and/or out of the chamber. Preferably the conduit means serve forleading the pressurized fluid into the chamber, and the fluid leaves thechamber through the clearance between the plug and its seat.

In a further preferred embodiment the machine comprises a first and asecond pump for pumping, respectively, a first and a second component ofsaid product, respective flow paths for the components between the pumpsand respective sterile sources of the components and between the pumpsand a common outlet for filling the containers, wherein the plug valveis constructed and situated to control the flow of the componentsthrough the flow paths and is angularly displaceable between a firstposition in which the first pump is in a discharge mode and dischargesthe first component via the plug into the outlet, and the second pump isin a suction mode and fills itself with the second component via theplug, and a second position in which the operation of the pumps isreversed.

Preferably each of the pumps is a singleacting reciprocating piston pumpwhich comprises a cylinder, a main piston and an auxiliary pistoncarried by a common piston rod, wherein the cylinder is fluid-tightlydivided by a rolling diaphragm into a main part containing the mainpiston and an auxiliary part containing the auxiliary piston, theperiphery of the rolling diaphragm being attached to the cylinder and acentral portion of the diaphragm is attached to the auxiliary piston tobe displaced thereby.

In an advantageous embodiment the main part of the cylinder has apumping portion the diameter of which is complementary to the diameterof the main piston, and a withdrawal portion which merges into thepumping portion but is of a larger diameter than the latter, the pumpbeing so designed that in its pumping mode the main piston isreciprocable within the pumping portion, while outside the pumping modethe main piston may be withdrawn into the withdrawal portion where allits surfaces are exposed for cleaning and sterilization.

DRAWINGS

The invention will now be described, by way of example only, withreference to the accompanying diagrammatic drawings showing an asepticfilling machine for filling a succession of plastics pots with aproduct, the machine comprising two piston pumps and a plug valve. Inthe drawings:

FIG. 1 is a simplified cut-away isometric view of the machine in itssolids filling mode;

FIG. 2 shows a plug of the valve in the solids filling mode;

FIG. 3 shows the machine in its liquid filling mode;

FIG. 4 shows the plug in the liquid filling mode;

FIG. 5 is a side elevation, partly in section, of the machine in itsliquid filling mode;

FIG. 6 is a plan to FIG. 5;

FIG. 7 is an axial section of one of the pumps;

FIG. 8 shows the machine in its cleaning mode; and

FIG. 9 is a section side elevation showing the machine in itssterilization mode with the plug of the valve and pistons of the pumpswithdrawn.

DETAILED DESCRIPTION

At the filling station (FIGS. 1 and 3) an indexing conveyor (not shown)carries a series of pot carriers 10 horizontally, below a main baseplate12 of the aseptic filling machine. The region below the baseplate 12 isenclosed and supplied with sterile air so that the pots 14 receive theproduct components through a filling nozzle 26 which has a verticalaxis, is provided with a flared outlet and is mounted in a hole 16 inthe baseplate 12 in a sterile environment. However the outlet need notnecessarily be flared as shown; for example a cylindrical outlet may beused. The product components reach the nozzle 26 through the sterilizedinterior of the machine, which is mounted on top of the baseplate 12.

The product components, namely the solids 18 and liquid 20 (both ashereinbefore defined) are supplied sequentially to the pot 14 by areciprocating solids metering pump 22 and liquid metering pump 24, anddo not become mixed until the liquid is added to the solids already inthe pot 14. Each of the pumps 22, 24 is substantially a single-actingpiston pump.

The machine includes a rotary plug valve 30 (FIGS. 1, 3, 5, 8 and 9)which acts both as a control valve and a cut-off valve. The valvecomprises a body or housing 28 provided with a tapered bore 29 whichforms a frusto-conical valve seat accommodating a complementarilytapered plug 32 to enable a plain surface-to-surface sealing betweenports without the use of additional elastomeric seals. If desired, an"O" ring or other elastomeric seal may be provided adjacent the widerend of the conical plug wall because, in this location, it will neverhave to pass a port during assembly or dismantling. The tapered bore 29is open at its small-diameter front end and extends axially past theplug 32 at its large-diameter rear end where it is closed by a plate 38,whereby a valve chamber 31 is formed behind the plug 32. The plug 32 hasa stem which passes through the chamber 31 and serves for angular andaxial displacement of the plug 32 as hereinafter explained. A channel 35opens into the chamber 31 for leading pressurized fluid into (and/or outof) the chamber 31.

Both the housing 28 and the plug 32 may be made of the same material,e.g. metal, or from different materials, for instance from differentmetals or one of them may be of plastics and the other of metal.

The vertex angle of the tapered plug 32, which has the shape of afrustrum of a right circular cone, is in the range of 15° to 45°,preferably 20° to 25°, and its axis extends to the bottom surface of thehousing 28 (and also the top and bottom surfaces of the baseplate 12) atan angle corresponding to one half of the vertex angle, i.e. to an anglebetween the axis of the plug and any of the generators of its surface.As a consequence, the portion of the housing 28 between the plug 32 andthe baseplate 12 below the axis of the plug 32 is uniformly thick. Theaxis of the nozzle 26 and the axis of the plug 32 intersect each other.

The valve 30 is designed to control and cut off the flow of both thesolids 18 and liquid 20 and consequently comprises two separate flowsystems, namely a solids flow system and a liquid flow system.

The solids flow system comprises a first chamber 46 which extendsaxially, is open at the narrow front end of the plug 32 and communicateswith a radial port 48 in the side of the plug 32. The solids flow systemalso includes an inlet port provided in the housing 28 and communicatingwith the outlet end of a solids feed pipe 52 the inlet end of whichcommunicates with a sterile source of solids (not shown).

The liquid flow system comprises a second chamber 42 which communicatesdirectly with ports 40 and 44 and via a longitudinal passage 54 (FIG. 5)with a port 46 in which a spray nozzle 58 provided with a plurality ofsmall openings therethrough is detachably secured by a long stud 60. Thepurpose of the small openings is to prevent undesirable outflow of theliquid after completed discharge stroke of the liquid metering pump 24.The ports 40, 44 and 56 are radial ports in the side of the plug 32. Inthe illustrated embodiments the axes of the ports 40 and 44 arecontained in a first radial plane of the plug 32 and are spaced throughan angular distance o, while the ports 48 and 56 are contained in asecond radial plane of the plug 32 and are spaced through an angulardistance o. In the illustrated example the radial distance o is 90°. Theliquid flow system also includes ports 88 and 37 provided in the housing28 and spaced through an angular distance o. The port 37 is an inletport communicating with the outlet end of a liquid feed pipe 36 theinlet end of which communicates with a sterile source of liquid (notshown).

Both the flow systems have a common outlet port 49 in the housng 28. Theoutlet port 49 communicates with the filling nozzle 26.

As seen in FIGS. 1, 3, 5, 8 and 9, the solids metering pump 22 ismounted on the base plate 12 via a hollow mounting block 84. The block84 is provided with a conduit 15 which communicates at one end with theopen end of the tapered bore 29 and thereby with the chamber 46 and atthe other end, via a valve (not shown) with an outlet (not shown). Theblock 84 is further provided with a profiled port 86 which is offsetfrom the axis of the pump 22 and through which the pump 22 communicateswith the conduit 15. The liquid metering pump 24 communicates throughthe port 88 in the housing 28 with the tapered bore 29.

The plug 32 is rotatably displaceable through an angular distance obetween two angular positions by a suitable rotary actuator 34 (FIG. 5).These two positions are a first position, shown in FIGS. 1 and 2, and asecond position shown in FIGS. 3, 4 and 5. In both positions, thechamber 46 in the plug 32 communicates with the conduit 15 and thereby,via the port 86, with the pump 22.

When the filling machine is in its solids filling mode (FIG. 1), theplug 32 is in the first position, in which the port 40 is aligned withthe inlet port 37 while the port 44 is aligned with the port 88, so thatthe liquid feed pipe 36 communicates via the ports 37 and 40, thechamber 42 and the ports 44 and 88 with the liquid metering pump 24which is in the suction mode so that the liquid 20 is supplied theretofrom the sterile source of liquid. In this position the port 56 issealed off by the surface of the tapered bore 29. At the same time, theport 48 is aligned with the outlet port 49 so that the filling nozzle 26communicates with the solids metering pump 22 which is in the dischargemode and consequently is delivering solids 18, via the port 86, conduit15, chamber 46, outlet ports 48 and 49 and the nozzle 26, into the cup14 below the nozzle 26.

When the delivery of solids into the cup 14 is completed, the fillingmachine is switched over to its liquid filling mode (FIGS. 3 and 5). Forthis purpose the core 32 is rotated to the second position as indicatedby arrow 50 in FIG. 4. In this position the port 48 is aligned with theinlet port 53 so that the solids feed pipe 52 communicates via the ports53 and 48, the chamber 46, conduit 15 and port 86 with the solidsmetering pump 22, which is now in the suction mode so that the solids 18are supplied thereto from the sterile source of solids. In this positionthe port 40 registers with the port 88, the port 44 is sealed off by thesurface of the tapered bore 29, and the port 46 is in register with theoutlet port 49 so that the filling nozzle 26 communicates with theliquid metering pump 24, which is in the discharge mode and consequentlyis delivering liquid 20, via the ports 88 and 40, chamber 42, thepassage 54, ports 56 and 49, and the nozzle 26, into the cup 14 whichhas been filled with solids.

The port 86 is preferably designed to direct the solids, withoutblockage, in the direction towards the valve 30 when the pump 22 isdischarging.

When delivery of the liquid stops, the filling machine is switched overto its solids filling mode. For this purpose the plug 32 is rotated inthe opposite direction (see arrow 62, FIG. 2), to restore it to itsfirst position. Indexing of the pot carriers 10 to present a new emptypot 14 to the nozzle 26 takes place before the plug 32 is rotated, afterwhich the new pot 14 is filled with solids and then liquid as describedabove.

As is apparent from the preceding description, mixing takes place in thecontainer 14 itself and not normally in the filling machine (though anarrangement is not excluded in which, while one pump is being charged,two or more other pumps are simultaneously discharging into thecontainer via a common mixing chamber in the control valve or upstreamof it).

In the case where two pumps 22, 24 are used, each pump is being charged(suction mode) while the other is being discharged (discharge mode),movement of the control valve plug 32 between its two positions beingtimed so as to bring, at or just after the end of the charging stroke ofthe pump being charged, that pump into communication with the container.This gives a "see-saw" action to the pumps, and enables mixed productsto be packaged quickly.

The two pumps 22 and 24 are preferably of generally similarconstruction, for example as shown in FIG. 7, having a cylinder 64formed from an upper block 66 and a lower block 68. The latter istapered at its top end (as shown at 70) to a larger bore, the upperblock 66 having the same larger bore. At the taper 70 is a radial inletand outlet connection 72 for communicating with the lower block 68 ofthe cylinder 64. The cylinder is divided into an upper part and a lowerpart by a rolling diaphragm 74 whose outer flange is clamped between thetwo cylinder blocks 66, 68 and whose top surface is at its centralportion secured to an upper piston 76 which supports the diaphragm 74and is situated above it. Piston 76 is carried on a piston rod 78 havinga working piston 80 at its front end. The piston 80 has sliding seals 82and slides in the reduced bore of the lower cylinder block 68. Due tothis arrangement the upper piston 76 is always contained in the upperpart, while the working piston 80 is always contained in the lower part.

The seals 82 provide primary sealing against ingress of product into thecylinder 64 above the piston 80, and greatly reduce the chance of damageto the diaphragm 74 by abrasive elements in the product. The diaphragm74 itself not only provides a secondary seal against ingress of product,but also serves as a barrier between the sterile lower part of thecylinder 64 and its upper part which is not in a sterile environment.Sterile fluid, such as sterile air, is introduced during normaloperation through the connection 72 into the sterile lower part of eachcylinder between the diaphragm 74 and the piston 80 not only to keepthat part sterile but also to prevent the product component pumpedtherein from getting past the piston 80 and its seals 82 above thepiston 80.

Each pump 22, 24 has a transverse yoke 90 mounted on its piston rod 78and coupled with a double-acting fluid actuator 92 to raise and lowerits pistons 76, 80. The length of the piston stroke of each pump 22 and24 is adjustable independently by any suitable means. FIG. 5 shows onepossible arrangement, in which the upper limit is set by a stop 94adjustable by a manual wheel 96. An actuator 98 for each pump controls aplate 100 pivoted at 102 on a fixed bracket. When in the position shownin FIG. 5, the plate 100 prevents the yoke 90 from rising until suchtime as it is necessary to raise the piston clear of the narrower basefor sterilizing.

Periodically the equipment needs cleaning and sterilizing. FIG. 8 showsthe cleaning mode, in this example by washing (though steam purging maybe used instead). Washing fluid is introduced simultaneously through thefeed pipes 36, 52, which are temporarily disconnected from the sterilesources of liquid and solids and are connected to a source of washingfluid, and the plug 32 is oscillated repeatedly back and forth betweenits two positions, while the pistons 80, 76 of the pumps 22, 24 arereciprocated repeatedly up and down. Wash effluent escapes through theconduit 15 (to the left in FIG. 8) and through the nozzle 26.

During the last part of the washing phase, the plug 32 is withdrawn inthe direction of arrow 33 axially to provide clearance between themating surfaces of the plug 32 and bore 29 but retaining a clearancebetween the rear face of the plug 32 and the closing plate 38, so thatall surfaces of the plug 32 are exposed for cleaning and subsequentsterilisation. Also, both the working pistons 80 are withdrawn, i.e.raised above the level of the tapers 70 into their enlarged chambers tothe same position as shown in FIG. 9, to provide clearance between thepistons 80 with their seals 82 and the inner surface of the cylinder 64.Sanitizing fluid is then introduced under pressure so that it contactsall internal surfaces and penetrates as far as the diaphragms 74. Thesteps used in the cleaning mode (washing, rinsing, sanitizing) and thefluids used therefor depend on the product components used for filling.After non-greasy components washing with a washing fluid might besatisfactory.

After completed washing and with pistons 80 and plug 32 retained intheir withdrawn positions sterilization can be carried out as shown inFIG. 9. For this purpose steam is introduced through the channel 35 intothe chamber 31 and from there flows around the plug 32 and around thepistons 80 and leaves through the connections 72. While cleaning isperformed after filling shift, sterilization is performed before afilling shift.

We claim:
 1. A machine for filling packaging containers with a flowableproduct wherein the product has first and second components, the machinecomprising a control valve in the form of a plug valve having a bodydefining a bore having a frusto-conical valve seat, a frusto-conicalplug having a frusto-conical surface, said valve seat having afrusto-conical surface complementary with said plug, a valve chamber forpressurized fluid being formed at the wider end of the plug, the chambercommunicating with the bore, the plug being axially displaceable betweena first position, in which its frusto-conical surface seals against thevalve seat and in which it is rotatable to control flow through thevalve, and a second position, in which it is withdrawn into the chamberto provide clearance between the surfaces of the plug and the seat butretaining clearance between its wider end and the surfaces of thechamber so that all surfaces of the plug are exposed for cleaning andsterilization.
 2. A machine according to claim 1 comprising conduitmeans communicating with the valve chamber for leading the pressurizedfluid into and/or out of the chamber.
 3. A machine according to claim 1or 2 wherein the product has two components and wherein the plugcomprises two separate flow paths for discretely directing the flow ofeach of said two components of the flowable product therethrough.
 4. Amachine according to claim 1 comprising a first and a second pump forpumping, respectively, said first and second components of said product,where the first and second components are of first and second sterilesources, and the machine is provided with a common outlet for fillingthe containers, respective flow paths for the components between thepumps and said respective sterile sources of the components and betweenthe pumps and said common outlet for filling the containers, wherein theplug valve is constructed and situated to control the flow of thecomponents through the flow paths and is angularly displaceable betweena first position in which the first pump is in a discharge mode anddischarges the first component via the plug into the outlet, and thesecond pump is in a suction mode and fills itself with the secondcomponent from the second source via the plug, and a second position inwhich the operation of the pumps is reversed such that the first pump isin a suction mode and the second pump is in a discharge mode.
 5. Amachine according to claim 4 wherein each of the pumps is asingle-action reciprocating piston pump which comprises a cylinder, amain piston and an auxiliary piston carried by a common piston rod,wherein the cylinder is fluid-tightly divided by a rolling diaphragminto a main part containing the main piston and an auxiliary partcontaining the auxiliary piston, the periphery of the rolling diaphragmbeing attached to the cylinder and a central portion of the diaphragm isattached to the auxiliary piston to be displaced by the auxiliarypiston.
 6. A machine according to claim 5 wherein the main part of thecylinder has a pumping portion, the diameter of which is complementaryto the diameter of the main piston, and a withdrawal portion, whichmerges into the pumping portion and is of a larger diameter than thepumping portion, each said pump being so designed that it has a pumpingmode in which the main piston is reciprocable within the pumpingportion, while outside the pumping mode the main piston may be withdrawninto the withdrawal portion in which its surfaces are exposed forcleaning and sterilization.